511 Network Authentication Required 是一种HTTP协议的错误状态代码，表示客户端需要通过验证才能使用该网络。
该状态码不是由源头服务器生成的，而是由控制网络访问的拦截代理服务器生成的。
网络运营商们有时候会在准许使用网络之前要求用户进行身份验证、接受某些条款，或者进行其他形式的与用户之间的互动（例如在网络咖啡厅或者机场）。他们通常用用户设备的 MAC 地址来进行识别。
511 Network Authentication Required
| Specification | Title |
|---|---|
| RFC 6585, section 6: 511 Network Authentication Required | Additional HTTP Status Codes |
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AcceptAccept-CharsetAccept-EncodingAccept-LanguageAccept-RangesAccess-Control-Allow-CredentialsAccess-Control-Allow-HeadersAccess-Control-Allow-MethodsAccess-Control-Allow-OriginAccess-Control-Expose-HeadersAccess-Control-Max-AgeAccess-Control-Request-HeadersAccess-Control-Request-MethodAgeAllowAuthorizationCache-ControlConnectionContent-DispositionContent-EncodingContent-LanguageContent-LengthContent-LocationContent-RangeContent-Security-PolicyContent-Security-Policy-Report-Only [我来译!]Content-TypeCookieCookie2DNTDateETagExpectExpiresForwardedFromHostIf-MatchIf-Modified-SinceIf-None-MatchIf-RangeIf-Unmodified-SinceKeep-AliveLarge-Allocation [我来译!]Last-ModifiedLocationOriginPragmaProxy-AuthenticateProxy-AuthorizationPublic-Key-PinsPublic-Key-Pins-Report-Only [我来译!]RangeRefererReferrer-PolicyRetry-AfterServerSet-CookieSet-Cookie2SourceMap [我来译!]HTTP Strict Transport SecurityTETk [我来译!]TrailerTransfer-EncodingUpgrade-Insecure-RequestsUser-AgentVaryViaWWW-AuthenticateWarningX-Content-Type-OptionsDNS 预读取X-Forwarded-ForX-Forwarded-HostX-Forwarded-ProtoX-Frame-Options 响应头X-XSS-Protection100 Continue101 Switching Protocol200 OK201 Created202 Accepted203 Non-Authoritative Information204 No Content205 Reset Content206 Partial Content300 Multiple Choices301 Moved Permanently302 Found303 See Other304 Not Modified307 Temporary Redirect308 Permanent Redirect400 Bad Request401 Unauthorized403 Forbidden404 Not Found405 Method Not Allowed406 Not Acceptable407 Proxy Authentication Required408 Request Timeout409 Conflict410 Gone411 Length Required412 Precondition Failed（先决条件失败）413 Payload Too Large414 URI Too Long415 Unsupported Media Type416 Range Not Satisfiable417 Expectation Failed426 Upgrade Required428 Precondition Required429 Too Many Requests431 Request Header Fields Too Large451 Unavailable For Legal Reasons500 内部服务器错误501 Not Implemented502 Bad Gateway503 Service Unavailable504 Gateway Timeout505 HTTP Version Not Supported511 Network Authentication Required [我来译!]CSP: base-uri [我来译!]CSP: block-all-mixed-content [我来译!]CSP: child-src [我来译!]CSP: connect-src [我来译!]CSP: default-src [我来译!]CSP: font-src [我来译!]CSP: form-action [我来译!]CSP: frame-ancestors [我来译!]CSP: frame-src [我来译!]CSP: img-src [我来译!]CSP: manifest-src [我来译!]CSP: media-src [我来译!]CSP: object-src [我来译!]CSP: plugin-types [我来译!]CSP: referrer [我来译!]CSP: report-uri [我来译!]CSP: require-sri-for [我来译!]CSP: sandbox [我来译!]CSP: script-src [我来译!]CSP: style-src [我来译!]CSP: upgrade-insecure-requests [我来译!]CSP: worker-src [我来译!]